The present invention pertains to the art of combined cycle power plants and, more particularly, to a combined cycle power plant having a reheat gas turbine and an exhaust gas regenerator.
In general, gas turbine engines combust a fuel/air mixture to release heat energy to form a high temperature gas stream that is channeled to a turbine section via a hot gas path. More specifically, a compressor compresses incoming air to a high pressure. The high pressure air is delivered to a combustion chamber to mix with fuel and form a combustible mixture. The combustible mixture is then ignited to form a high pressure, high velocity gas stream that is delivered to a turbine. The turbine converts thermal energy from the high temperature, high velocity gas stream to mechanical energy that rotates a turbine shaft. The turbine shaft is coupled to, and drives, the compressor as well as also other machinery coupled to the turbine such as, an electrical generator.
After converting the thermal energy from the high pressure, high velocity gas stream to mechanical energy, exhaust gases are formed and vented from the turbine. The exhaust gases can either be expelled to ambient air, or used to preheat the combustion chamber and increase turbine efficiency. Optimizing turbine efficiency at various operating conditions, particularly at part load where emissions are typically at high levels is a concern.